On 25 April 2015, the Special Chamber of the International Tribunal for the Law of the Sea (ITLOS) formed to deal with the dispute concerning delimitation of the maritime boundary between Ghana and Côte d’Ivoire in the Atlantic Ocean (Case No. 23) issued its Order on the request for the prescription of provisional measures filed by Côte d'Ivoire.

take all steps to suspend all ongoing oil exploration and exploitation operations in the disputed area;

refrain from granting any new permit for oil exploration and exploitation in the disputed area;

take all steps necessary to prevent information resulting from past, ongoing or future exploration activities conducted by Ghana, or with its authorization, in the disputed area from being used in any way whatsoever to the detriment of Côte d'Ivoire;

and, generally, take all necessary steps to preserve the continental shelf, its superjacent waters and its subsoil; and

desist and refrain from any unilateral action entailing a risk of prejudice to the rights of Côte d'Ivoire and any unilateral action that might lead to aggravating the dispute.

Ghana requested the Special Chamber to deny all of Côte d'Ivoire's requests for provisional measures.

In relation to Côte d'Ivoire's submissions to the effect that the measures are needed to prevent serious harm to the marine environment, the Special Chamber holds that Côte d'Ivoire has not adduced sufficient evidence to support its allegations that the activities conducted by Ghana create an imminent risk of serious harm to the marine environment (para. 67). Nevertheless, the Chamber underlines that the risk of serious harm to the marine environment is of great concern to the Special Chamber (para. 68) and reaffirms that 'the duty to cooperate is a fundamental principle in the prevention of pollution of the marine environment under Part XII of the Convention and general international law and that rights arise therefrom which the Tribunal may consider appropriate to preserve under article 290 of the Convention' (para. 73).

In the view of the Special Chamber, an order suspending all exploration or exploitation activities by or on behalf of Ghana in the disputed area, including activities relating to drilling that has already taken place, would cause prejudice to the rights claimed by Ghana and an undue burden on it (para. 100). On the other hand, however, the Special Chamber considers it appropriate, in order to preserve the rights of Côte d'Ivoire, to order Ghana to ensure that no new drilling by or on behalf of Ghana takes place in the disputed area (para. 102).

In the light of these considerations, the Special Chamber unanimously prescribes two cooperation obligations for Ghana and Côte d’Ivoire among the provisional measures it orders.

First, the Special Chamber orders that:

'The Parties shall take all necessary steps to prevent serious harm to the marine environment, including the continental shelf and its superjacent waters, in the disputed area and shall cooperate to that end' (para. 108, 1(d)).

The Special Chamber further prescribes that:

'The Parties shall pursue cooperation and refrain from any unilateral action that might lead to aggravating the dispute.' (para. 108, 1(e)).

The inclusion of obligations to cooperate in orders on provisional measures has steadily become a fixture in the case law of the ITLOS in cases involving risks to the marine environment. However, the present Order has added another important dimension to the inclusion of cooperation obligations by stipulating an obligation to pursue cooperation linked to the obligation to refrain from action that might aggravate the dispute. In doing so, this provisional measure provides a welcome clarification of the positive corollary to the negative obligation of non-aggravation and should be kept in mind in interpreting and applying articles 74(3) and 83(3) of the United Nations Convention on the Law of the Sea.